Form Validation: Name & City

Please help. For the past day I have been trying to make regular expressions to check the first and last name, the city.
let’s say:

$name=' ';

How to prevent characters other than Russian letters and spaces in the name, and in the location – except Russian letters?
Thanks in advance!

Answer 1, authority 100%

preg_match('/^[--\s]+$/u', $name)
preg_match('/^[--]+$/u', $location)

Answer 2, authority 100%

if(preg_match('~[^-- ]~u', $name)) {
   echo "   ";

There can be 2 words in a city + it can be written with a dash.

if(preg_match('~[^--\- ]~u', $location)) {
   echo "   ";